1. Field of the Invention
The present invention relates to a sprayable cosmetic or dermatological formulation comprising a lipid-containing preparation and one or more propellant gases selected from hydrofluorocarbons, n-butane, isobutane and propane.
The formulation permits the application of a cosmetic preparation to the skin by spraying an otherwise non-sprayable preparation.
2. Discussion of Background Information
In known aerosol atomizers or spray cans, a liquid contained therein is held under pressure by a propellant present in the container and is expelled through a nozzle to form an atomized jet. Constituents of the spray can are the liquid and/or gaseous propellant since this generates the necessary pressure for spraying, and the actual product—the active ingredient, the preparation, which is to be sprayed. The product to be applied is gaseous or liquid and/or mixed in the can with the propellant, the propellant gas.
As a result of the internal pressure in the spray can, its contents are released precisely as aerosol if the spray head is pressed. The secret of this function mode lies in the mixture of active ingredient (the actual product) and liquid propellant inside of the spray can: some of the propellant is dissolved in the active ingredient and some is in gaseous form as “pressure cushion” above the active ingredient/propellant mixture. If the spray head is actuated, the gaseous propellant forces the contents through the valve to the outside. At this moment, the propellant evaporates in fractions of seconds and the remaining active ingredient distributes itself finely and evenly.
Some active ingredients cannot be mixed directly inside the can with a propellant. For example, the active ingredients/products/preparations to be discharged are often unstable towards the propellant.
In particular, products which are per se sprayable only with difficulty, if at all, such as high viscosity formulations, such as pastes, creams or high viscosity gels or emulsions, can be sprayed with difficulty or not at all.
With the help of aerosol technology and the packaging format of the “two-chamber aerosols”, these cream-like or thick-liquid substances can be contained in a spray can and discharged from this. However, in the so-called “bag-in-can” or “bag-on-valve” systems, the propellant gases are not in direct contact with the formulations to be discharged.
In further known cosmetic aerosol preparations, the propellant gases are predominantly mixtures of butane, isobutane and propane at a pressure level of 2.7 bar.
Frequent presentation forms of these cosmetic or dermatological preparations are finely dispersed multiphase systems in which one or more fat or oil phases is/are present alongside one or more water phases. Among these systems, the actual emulsions are in turn the most widespread.
The term “cosmetics” summarizes all measures which, for esthetic reasons, bring about changes to skin and hair or are used for cleaning the body. Cosmetics thus means to care for, to improve and/or to beautify the outside of the body in order to please, in a visible, palpable and olfactory manner, both fellow beings as well as oneself. Cosmetics has been used by people for this purpose for centuries. This included coloring lips and face, anointing with valuable oils and bathing in scented water.
One property of cosmetic products that is very important to the consumer but can only be quantitatively measured with difficulty is their texture. The term “texture” is understood as meaning those properties of a cosmetic which are attributed to the structure of the preparation, are perceived by the sense of touch and contact and can possibly be expressed in mechanical or rheological flow properties. The texture can be tested in particular by means of sensorics. The texture of cosmetic products that may be influenced with the help of additives is of virtually identical importance to the consumer as their objectively ascertainable effects.
The term “sensorics” is used to refer to the scientific discipline which deals with the evaluation of cosmetic preparations on the basis of sensory impressions. The sensory assessment of a cosmetic takes place by reference to the visual, olfactory and haptic impressions.                Visual impressions: all features perceptible to the eye (color, shape, structure).        Olfactory impressions: all odor impressions perceptible upon drawing in air through the nose, which can often be differentiated into initial odor (top note), main odor (middle note, body) and end note (finale). The volatile substances released only upon application also contribute to the olfactory impression.        Haptic impressions: all sensations of the sense of touch, which relate primarily to structure and consistency of the product.        
The sensory analysis makes use of the possibility of integrally ascertaining the sensory overall impression of a product. Disadvantages of sensory analysis are the subjectivity of the impression, the easy influencing of the subjects and the considerable scattering of the results brought about as a consequence. These weaknesses are countered nowadays by using groups of trained subjects, mutual screening of the examiners, as well as statistical evaluation of the mostly numerical analysis data.
The removal, application and spreading of high viscosity preparations on the skin is furthermore beset with problems for the user and is often unacceptable from a sensory perspective.
The very removal and application of thick-liquid or pasty preparation using the fingers from a jar or a tube is unpleasant or difficult to dose. It would be desirable to provide a contactless removal option.
Contactless application means, for example, by means of a spatula or spoon or by being able to spray the preparation.
However, high viscosity substances are not easy to spray without considerable expenditure in terms of apparatus or formulation technology.
It was therefore an object to provide topical formulations comprising lipid-containing, in particular high viscosity, preparations which can be applied in a contactless manner and can be applied to and spread on the skin in an easy and sensorily acceptable manner.
Preferred topical preparations are cosmetic, dermatological or pharmaceutical preparations, in particular cosmetic preparations.
Moreover, it is desirable to provide an application option for different cosmetic or dermatological preparations.
Cosmetic aerosols, such as e.g. deodorants, are known. However, these usually comprise emulsions and are water-containing.
Moreover, foot sprays are known, such as the spray from Aurena® as Petrolatum Spray or Apresan® and Scholl® foot spray. The latter are again water-containing preparations, emulsions which moreover comprise a customary propellant gas mixture.
The petrolatum foot spray is a so-called bag-on-valve system, meaning that there is no direct contact between the propellant gases and the preparation to be applied contrary to the desired execution.
U.S. Pat. No. 8,795,635 B2, the entire disclosure of which is incorporated by reference herein, describes foamable preparations comprising, besides customary propellant gases, 25 to 95% of petrolatum, 1 to 70% of a hydrophobic solvent and 0.1 to 20% of an agent which is responsible for the foam formation, in particular surfactants. The preparations are free from water, short-chain alcohols and silicones.
US 20120189557 A1, the entire disclosure of which is incorporated by reference herein, discloses formulations containing propellant gas which, for the application of cosmetic or pharmaceutical preparations, require the addition of readily volatile carrier liquids, in particular readily volatile silicones.
WO 20140434487 A2, the entire disclosure of which is incorporated by reference herein, describes antiperspirant preparations which have a propellant gas fraction of 30 to 65% by weight. The viscosity of the propellant-gas-free preparation is more than 1000 cP. In order to be able to apply these preparations as aerosol, a fraction of nonvolatile silicones of more than 40% by weight is prescribed as being obligatorily necessary.
WO 2011064631 A1 and US 20130064777 A1, the entire disclosures of which are incorporated by reference herein, describe water- and surfactant-free preparations which comprise hydrophobic solvents, a wax and propellant gases. The propellant gas fraction here is at most 30% and preferred propellant gases are mixtures of propane, isobutane and butane with at most 27% n-butane. For propellant gas fractions above 30%, no foams are obtained according to the description.
U.S. Pat. No. 8,663,692 B1, the entire disclosure of which is incorporated by reference herein, describes lipid particle dispersions of a mixed matrix of solid lipid and liquid lipid. The dispersions can be sprayed, possibly following dilution with water, using standard commercial devices or be atomized as aerosol. An essential constituent here is water or a water-miscible liquid.
U.S. Pat. No. 8,349,297 B1, the entire disclosure of which is incorporated by reference herein, describes a pharmaceutical formulation which, upon topical administration, can form a film, where the formulation has a preparation of a pharmaceutical, a solvent therefor, a film former and a propellant.
So-called Vaseline sprays are known from another technology sector, the building sector.
These include solvents such as petroleum spirit or alcohols which are able to dissolve the Vaseline so as then to allow discharge using known propellant gases and apparatuses.
Alcohols, in particular short-chain alcohols, such as ethanol or isopropanol, can dry out the skin and often lead to burning, unpleasant cooling effect and/or skin irritations upon application.
It would therefore be advantageous to have available a topical, preferably cosmetic, formulation which does not have the disadvantages of the prior art. A problem here is that avoiding one disadvantage often leads to another disadvantage.
It is therefore desirable to provide a formulation where the number of ingredients can be limited to a minimum. In particular, it is necessary to dispense with skin-irritating, readily volatile substances, such as solvents, e.g. ethanol or petroleum spirit, foam formers, such as surfactants, and with silicones since these would hinder the skincare aspect and in particular the application-friendly application.